Telephone answering device

ABSTRACT

A microprocessor controlled telephone answering device displays a message number and the date and time received for each recorded message as the message is played back. Other features include a cue function for selecting messages as they are played back. The answering device can automatically rewind back and locate a cued message to replay that selected message. Also, digital function codes can be transmitted over a telephone by a remote control unit to control a large number of answering device functions from a remote location. Additional features include the capability for easily entering a new security code into both the answering device and the remote control unit.

This application is a division of application Ser. No. 324,154, filedNov. 23, 1981, now U.S. Pat. No. 4,469,919.

BACKGROUND OF THE INVENTION

1. Related Applications

Claim of priority is made for the present invention pursuant to 35U.S.C. §119 to obtain the benefit of the earlier filing dates in Japanof the following Japanese applications:

"Recording Tape Information Code System," filed Feb. 20, 1981,application number 56-23928;

"Remote Control Code System," filed Feb. 20, 1981, application number56-23929;

"Recording Tape Residual Quantity Sensing Apparatus of AutomaticTelephone Answering Device," filed Feb. 20, 1981, application number56-23930;

"Automatic Answering and Recording Apparatus," filed Feb. 20, 1981,application number 56-23931;

"Message Selection System for Automatic Recording Apparatus," filed Mar.23, 1981, application number 56-41893;

"Latest Recorded Information Discriminating System," filed Mar. 23,1981, application number 56-41894; and

"Message Recording System," filed Mar. 31, 1981, application number56-47688.

2. Field of the Invention

The present invention relates to telephone answering devices, and moreparticularly, to a telephone answering device which is fully controlledby a microprocessor. In addition to controlling all the standardtelephone answering device functions, the microprocessor enables theimplementation of a variety of novel features which significantlyincrease the usefulness as well as convenience of a telephone answeringdevice. These additional features are accomplished without addingsignificant complexity to the design of the device.

Telephone answering devices often use two separate cassette-type taperecorder/playback apparatuses (hereinafter "tape drives"). One tapedrive is used to play back a prerecorded outgoing message orannouncement from one of the cassettes when a call is received. Theannouncement typically states that the person is unavailable to come tothe phone and that a message may be recorded at the sound of a tone.When the caller hears the tone, he then dictates his message into thephone, which is recorded by the second or incoming message tape driveonto the second cassette tape. After the incoming message is completed(or when the time allotted for the message has expired), the incomingmessage tape drive stops. The answering device then waits until a newincoming message is received at which time the incoming message tapedrive is restarted. Each incoming message is sequentially recorded onthe incoming message cassette tape until the incoming message tape isfull or until the user returns to play back the recorded messages. Tolisten to the recorded messages, the user rewinds the incoming messagetape to the beginning of the tape and then places the second tape driveinto the playback mode. Each recorded message is then sequentiallyplayed back in the order in which it was received.

3. Description of the Prior Art

It is often highly desirable to know the exact date and time that aparticular message is received. This information is generally notprovided by typical prior art telephone answering devices. For example,U.S. Pat. No. 3,925,617 to Sato suggests automatically recording a voicetime-of-day signal from a radio onto a single track incoming messagetape at preset intervals (e.g., every 30 minutes). This time recordingis inhibited when an incoming message is being recorded. Thus theincoming message tape apparently contains consecutive voice time signalsinterspaced between the recorded incoming messages. The time signal isnot triggered by receipt of a call, hence it is not possible todetermine the exact time within the preset intervals that a particularmessage was received. Another device which records time-of-day signalsis suggested in U.S. Pat. No. 3,372,240 to Boyers.

It is an object of the present invention to provide a telephoneanswering device which automatically records date and time informationindicating when a message is received, and which displays such time anddate as that particular message is being played back.

Another problem encountered with previous telephone answering devices isthat after all the messages have been played back, the user oftendesires to play particular messages again which he may have foundinteresting. In order to do this with many prior art answering telephoneanswering devices, the user rewinds the incoming message tape to wherehe believes is the approximate location of the desired message. The tapeis then played back at that point until the user recognizes whether ornot the message being played is the desired message. If not, the userthen rewinds or fast forwards the message tape a certain distance andplays the tape again. The user continues in this trial and error methoduntil the desired message is found. The user then attempts to find thebeginning of that message.

In order to aid the user in finding a particular message, it has beenproposed in U.S. Pat. No. 3,141,931 to Zarouni to prerecord messagenumbers, usually by voice, on a separate track of the incoming messagetape. However, since the message numbers are prerecorded, thisnecessitates that the space provided for each message on the incomingmessage tape be fixed. Since actual messages are variable in length, theunused tape between messages is wasted. Furthermore, during playback,the user is required to wait during this dead space for the next messageto begin or otherwise must interrupt the playback mode to fast forwardthe incoming message recorder to the beginning of the next message. Inaddition, the user is still required to monitor the message number trackand rewind and fast forward until the desired message is found.

Other telephone answering devices have mechanical counters whichincrementally move a message number wheel each time a message isreceived. When a playback key is depressed, the tape is automaticallyrewound to the beginning of the tape which resets the message numberwheel to message number "one." The tape is then played back with themessage number wheel indicating the message number of each message as itis played. Again, the user must manually rewind and fast forward untilthe desired message is found.

It is an object of the present invention to provide an improvedtelephone answering device which can automatically locate and playbackmessages preselected by the user.

It is another object of the present invention to provide an improvedmessage numbering scheme for a telephone answering device for automaticcontrol of the playback of the messages.

The functions of "playback", "rewind", "fast forward", "stop", etc. aretypically controlled by keys or switches physically located on thetelephone answering device itself. Some answering devices have thecapability of having a few of these function operated from a remotelocation. The user, when absent from his answering device, can call andcontrol these functions of the device over the telephone. Prior arttelephone answering devices are typically controlled over the telephoneby a set of audio tones each of which has a unique frequency. Eachfunction is usually assigned one frequency (or combination offrequencies). The telephone answering device, upon receipt of aparticular frequency (or combination of frequencies) activates thecorresponding function.

The tones are typically generated by depressing the buttons of a "touchtone" phone (U.S. Pat. Nos. 3,141,931 to Zarouni and 3,904,826 to Murataet al.) or by a separate remote control unit or "beeper" which the userplaces near the mouthpiece of the phone. In either case, the telephoneanswering device usually has relatively complex tone discriminationcircuits to determine which tone of the set of control tones was sent,and to activate the corresponding function. Generally, the morefunctions that are controlled, the greater the number of tones requiredand consequently, the greater the complexity of the tone discriminationcircuits in the telephone answering device.

It is an object of the present invention, to provide a relatively simplesystem for operating a telephone answering device from a remote locationyet which is capable of controlling a large number of telephoneanswering device functions.

In order to prevent unauthorized persons from playing back the recordedmessages over the telephone, many telephone answering devices requirethe receipt of a particular security code before the telephone answeringdevice will respond to remote control. For example, U.S. Pat. No.4,196,311 to Hoven suggests transmitting a binary security code from theremote control unit to the telephone answering device. The particularbinary code sent is set by the positions of a number of switches locatedon the remote control unit. The telephone answering device has a similarnumber of switches which must be set to the identical positions of theswitches on the remote control unit. Thus if one or more switches on thetelephone answering device is inadvertently set incorrectly, then thetelephone answering device can not respond to the remote control unit.

It is an object of the present invention to provide a simple method ofentering a new security code which is displayed as it is entered.

It is another object of the present invention to provide a remotecontrol unit and telephone answering device system in which a newsecurity code entered into the telephone answering device isautomatically transmitted to the remote control device as well.

SUMMARY OF THE INVENTION

These and other objects and advantages are provided by a microprocessorcontrolled telephone answering device which has a dual track cassettetape recorder/playback apparatus for recording incoming messages. Themessages left by the callers are recorded on one track of the cassettetape. Digital signals which represent the date and time that aparticular message is received, are recorded on the other track whilethe caller's message is being recorded on the first track. Duringplayback of the messages, the digital signals are read off the secondtrack while the user listens to the messages on the first track. Theprocessor of the answering device inputs these digital signals anddisplays the date and time information for a particular message on adigital display while the user is listening to that particular message.In this manner, the user may learn when each message was recorded.

In another aspect of the present invention, a message number is assignedto each incoming message and is recorded in digital form on the secondtrack (in addition to the date and time digital signals) while thecaller's message is recorded on the first track. These message numberdigital signals may also be inputted by the processor to display themessage number while the message is being heard.

During playback of the recorded messages, if the user decides he maywant to hear again the message presently being played, a user input isprovided which, when actuated, causes the message number of the messagebeing played to be stored in the processor memory. In this manner, theuser can "cue" a particular message for later playback. Upon completionof the playback of the messages, the processor of the telephoneanswering device can read the number stored in memory and rewind themessage tape to the corresponding message for playback.

The message numbers may be utilized in other ways as well. For example,after the telephone answering device is placed into an "answer" mode torespond to incoming calls, the device can store the message number ofthe first message received. Additionally, when the device is placed inthe "playback" mode, the message number of the last message received canalso be stored. When placed in the playback mode, the device canautomatically rewind to the message corresponding to the initial messagenumber and begin playback so that old messages preceeding the newmessages need not be listened to. Furthermore, the device canautomatically stop upon completion of the playback of the last message.In this manner, if the new messages are recorded on a previously usedcassette, old messages found after the last new message also need not belistened to.

Other features utilizing the data stored on the data track include a"next message" function which allows the user to skip over unwantedmessages. The processor monitors the data track while a message is beingskipped and automatically resumes replay at the beginning of the nextmessage, which is marked by the data track.

In an additional aspect of the present invention, a remote control unitis provided which transmits digital function codes for control of thetelephone answering device. Each answering device function which can becontrolled from the remote control unit is assigned a unique digitalfunction code. A digital function code modulates an audio tone which isthen transmitted by the remote control unit when a key on the remotecontrol unit corresponding to that function is depressed by the user.The telephone answering device processor, upon receipt of the functioncode modulated audio tone, decodes the function code and initiates thefunction corresponding to that digital code. As will become more clearin the following detailed description, the telephone answering devicerequires only one tone decoder to demodulate the function codestransmitted from the remote control unit to digital signals recognizableby the telephone answering device processor.

In still another aspect of the present invention, a digital securitycode may be easily entered for the remote control unit to transmit tothe telephone answering device before transmitting any of the functioncodes. Before the remote control unit is taken away to be used, theremote control unit is connected to the telephone answering device andthe new code is entered into the telephone answering device bydepressing switches on the face of the device. Upon receipt of the newcode, the telephone answering device automatically enters the newsecurity code via the connector to the remote control unit where it isstored in a remote control units memory. In this manner, the securitycode is automatically changed in both the telephone answering device andthe remote control unit so that the user need not manually change thesecurity code in first one and then the other. The remote control unitis then disconnected and is ready for use.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial view of a telephone answering device and remotecontrol unit in accordance with a preferred of the present invention;

FIG. 2 is a schematic block diagram of the telephone answering deviceand remote control unit of FIG. 1;

FIG. 3 is a schematic diagram of a data modulator for the telephoneanswering device of FIG. 1;

FIG. 4 is a waveform representation of an example of the digitalinformation to be stored on the data track of the telephone answeringdevice of FIG. 1;

FIG. 5 is a waveform representation of the modulated digital informationof several messages stored on the data track;

FIGS. 6A-6C illustrate the demodulation of frequency shift key modulateddigital information;

FIG. 7A illustrates an example of a digital security code waveform;

FIG. 7B illustrates an example of a waveform representing a digitalfunction code;

FIG. 8 is a flow chart describing the operation of the processor of thetelephone answering device of FIG. 1 to accomplish the function ofrecording the incoming messages (ICM);

FIGS. 9A-9B are a flow chart describing the playback of incomingmessages by the telephone answering device of FIG. 1;

FIG. 10 is a flow chart describing the cue memory function of thetelephone answering device of FIG. 1;

FIG. 11 is a flow chart describing the "next message" function of thetelephone answering device of FIG. 1;

FIG. 12 is a flow chart describing the play of the outgoing announcement(OGA) of the telephone answering device of FIG. 1;

FIG. 13 is a flow chart describing the entry of a new security code intothe telephone answering device of FIG. 1;

FIG. 14 is a flow chart describing the operation of the remotecontroller for the telephone answering device of FIG. 1; and

FIG. 15 is a flow chart describing the operation of the telephoneanswering device of FIG. 1 upon receipt of a security code or a functioncode.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a telephone answering device 10 which employs a preferredembodiment of the present invention. The device 10 is coupled to atelephone line 12 to receive telephone calls placed to the user of thedevice 10. When a call is received, a prerecorded outgoing announcement(OGA) is played back from a first cassette tape 13 by a taperecorder/playback apparatus 14 (hereinafter OGA tape drive 14). Theannouncement usually states that no one is available to answer the phoneand that a message may be dictated by the caller at the sound of a toneat the end of the announcement. The message dictated by the caller, i.e.the incoming message (ICM), is recorded on a second cassette tape 15 bya second recorder/playback apparatus 16 (hereinafter ICM tape drive 16).The ICM cassette tape 15 has two tracks, a message track for recordingthe incoming message and a data track for recording digital informationsignals identifying the incoming message being recorded. In theillustrated embodiment, the message identification information includesa message number, the time that the message being recorded was received,as well as the date the message was received. This information isrecorded continuously and repetitively on the data track while theincoming message is being recorded on the message track of the ICM tape15.

The recording of the message identification information onto the ICMtape data track (as well as the message itself onto the message track)is performed under the control of a programmed microprocessor. Themicroprocessor, together with a program memory and data memory, forms amicrocomputer which implements this novel function as well as thefollowing inventive functions which will now be described.

To listen to the callers' messages, the ICM tape 15 is rewound and themessages recorded by the ICM tape drive 16 are played back. As the useris listening to the messages played back from the message track, thedevice 10 reads the digital message identification data recorded on thedata track and continuously displays this information on a display 18 asthe message is played back. For example, while the first messagerecorded by the ICM tape drive 16 is being played back, a "1" appears inthe display 18. The device 10 also has a plurality of display modeindicators 20 which label the information being displayed in the display18. Thus, while the message number "1" is being displayed in the display18, an LED (light emitting diode) indicator 22 beneath the label "MSG.NO." of the display mode indicators 20 is lit. After the message numberhas been displayed for a certain duration (for example, 3 seconds), thetime that the first message was received is indicated in the display 18and a "TIME" LED indicator 24 is lit. Subsequently, the date that thefirst message was received in shown in the display 18 and the "DATE" LEDindicator 26 is lit. In this manner, the message number, date and timeare sequentially and continuously displayed while the message is beingplayed back.

While the user is listening to the messages being played back, he maydecide that the message presently being played back is sufficientlyinteresting to listen to again. The device 10 has a "CUE" key or switch28, which when depressed by the user, causes the device 10 to store themessage number of the message presently being played back in the cuememory for later replay of the message. In the illustrated embodiment,up to three such message numbers may be stored for later playback. Uponcompletion of the playback of the recorded messages, the user may replaythe last message cued by again pressing the cue switch 28. The device 10then automatically rewinds to the beginning of the message correspondingto the last message number stored in the cue memory, replays thatmessage and stops. If the user has selected other messages for replay,the user may then depress the cue switch 28 again causing the device 10to rewind the ICM tape 15 to the beginning of the next selected messagefor replay.

The telephone answering device 10 also has a remote control unit 30which can operate the device 10 from a remote location. The remotecontrol unit 30 is shown in FIG. 1 connected to the device 10 through acable connector 42 which is only used when a new security is enteredinto both. During normal use, the device 10 and remote control unit 30are not connected together which allows the remove control unit to betaken away.

The remote control unit 30 has a keypad 32 of a plurality of functionkeys or switches to control the answering device 10. Each key controls aseparate answering device function such as "stop", "rewind", "fastforward", "cue", etc. The keys of key pad 32 duplicate similar functionswitches 34 located on the telephone answering device 10.

To operate the telephone answering device 10 from another location, theuser places a telephone call to his own number which the device 10answers. A speaker 36 is detached from the remote control unit 30 and isplaced adjacent the mouthpiece of the telephone handset. The speaker 36remains electrically connected to the remote control unit 30 by aflexible cord 37 which allows the remote unit 30 to be conveniently heldwhile the speaker 36 is placed near the telephone mouthpiece. When theremote control unit 30 is first turned on, the unit transmits a digitalsecurity code (such as that represented by the waveform shown in FIG.7A) to the answering device 10 over the telephone line 12. In theillustrated embodiment, this security code may represent any numberbetween 0 and 1999. If the answering device recognizes the security codetransmitted by the remote control unit 30 as the correct security code,the answering device 10 then enables itself to receive the functioncodes transmitted by the remote control unit 30, decode them, andimplement them. The answering device 10 will ignore any remote controlunit which does not transmit the correct security code.

Accordingly, after the remote control unit 30 is turned on (and thecorrect security code has been transmitted), the device 10 may becontrolled by depressing any of the function keys of the keypad 32. Uponactuation of a key, a digital code which corresponds to the desiredfunction is transmitted over the telephone line 12 to the answeringdevice 10. An example of one such digital function code is representedby the digital waveform shown in FIG. 7B. In the illustrated embodiment,the function codes are transmitted over the telephone line 12 by afrequency shift key technique.

The answering device 10 has an amplifier and filter circuit 38 and tonedecoder 40 (FIG. 2) which demodulate the function code transmitted fromthe remote control unit 30 back to an unmodulated signal as representedin FIG. 7B. The microcomputer 44 of the telephone answering device 10decodes the digital function code by recognizing which function isassociated with that function code, and performs the associatedfunction. The above described digital function codes are highlyadaptable to control a large number of functions without requiring acorrespondingly large number of frequencies or tones for transmittingthe various function codes. In the illustrated embodiment only twofrequencies are used for transmission and only one tone decoder is usedfor demodulation.

As previously mentioned, in order to initially set the security code orchange the security code, the device 10 and remote unit 30 are connectedtogether by the cable 42 before the remote control unit is taken awayfor use. The security code is easily entered into the device 10 byoperating certain switches 34 on the face of the device 10. When the newsecurity code is entered, the answering device 10 stores the securitycode in memory. The answering device 10 also automatically transmits thesecurity code over the cable 42 to the remote control unit 30 where itis also stored. In this manner, the new security code is automaticallyentered into both the answering device 10 and the remote control unit.The user may then disconnect the cable 42 from the remote control unitand the answering device 10.

Referring now to FIG. 2, a schematic block diagram of the telephoneanswering device 10 is shown. The answering device 10 includes amicrocomputer 44 which has a microprocessor (not shown), a programread-only-memory (ROM) 46 and a random-access-memory (RAM) 48. Themicrocomputer 44 stores the security code entered by the user in the RAM48. In addition, the message numbers cued during playback are alsostored in the RAM 48. The microcomputer 44 further has an input bus 50through which it reads the function switches or keys 34 of the answeringdevice 10. The microcomputer 44 detects whether any of the keys 34 havebeen depressed and carries out the indicated function.

During playback of the messages recorded on the ICM tape 15, themicrocomputer 44 outputs the message number, date and time informationon an output bus 52 to be displayed by the display 18. At the same time,the microcomputer 44 lights the appropriate mode LED 20 to correspondwith the information being displayed in the display 18.

The answering device 10 has a ring detector 54 connected to thetelephone line 12 to alert the microcomputer 44 to respond to a ringsignal. The ring detector 54 has an output connected to an inputinterface 56 which is connected to the microcomputer input bus 50. Ringdetector circuits are well-known in the art and the input expander 56may be an input multiplexer, for example.

The microcomputer 44 has an output bus 57 connected to an outputinterface 58 which may be an output multiplexer, for example. Themicrocomputer 44 controls the OGA tape drive 14 and ICM tape drive 16through the output interface 58. Accordingly, the output interface 58 isconnected to a motor speed and motor control circuit 60 which controlsthe OGA motor 62 and ICM motor 64 of the OGA tape drive 14 and ICM tapedrive 16, respectively. The motor speed and control circuit 60, underthe control of the microcomputer 44, turns the motors on and off,controls the speed (i.e. fast forward or normal) and the direction (i.e.forward or reverse). Such motor speed and control circuits are alsowell-known in the art. A head select circuit 66 activates either the ICMmessage track record/playback head 68 or alternatively the OGArecord/playback head 70 under the control of the microcomputer 44.

When an incoming call is detected by the ring detector 54, themicrocomputer 44 seizes the line (i.e., puts the device "off-hook") andinitiates proper commands to begin the answering cycle. Themicrocomputer 44 then starts the OGA motor 62 to playback theprerecorded announcement recorded on the OGA tape 13. Accordingly, themicrocomputer 44 selects the OGA record/playback head 70 and places itin the playback mode. The output of the OGA head 70 is connected to anamplifier 72 which is in turn connected to a filter 74 and a secondamplifier 76. The announcement recorded on the OGA tape 13 is amplifiedby the amplifers 72 and 74 and transmitted to the caller on thetelephone line 12.

In the illustrated embodiment, the OGA tape 13 is a continuous "endlessloop" tape. When the user initially records the announcement on the OGAtape 13, the device 10 records an 800 Hz tone on the remaining OGA tapewhen the announcement is completed to mark the end of the announcement.When a call is received, the 800 hertz tone indicates to the caller thatthe answering device 10 is ready to record his message. This 800 hertztone is detected by a tone decoder 78 connected to the output of theamplifier 72. Upon receipt of a signal from the tone decoder 78indicating that the end of the announcement has been encountered, themicrocomputer 44 starts the ICM motor 64 of the ICM tape drive 16 andturns off the OGA motor 62 (after the OGA tape 13 returns to the startof the tape). In addition, the ICM record/playback head 68 is selectedto record the caller's message on the ICM tape 15 of the ICM tape drive16. The caller's message from the telephone line 12 is amplified by anamplifier 80 and is transmitted to the ICM record/playback head 68 forrecording on the message track of the ICM tape.

As previously mentioned, as the caller's message is being recorded onthe ICM message track, digital message identification signals aresimultaneously recorded on the data track. In the illustratedembodiment, these digital signals represent the message number, timereceived and date received of the message being recorded. Themicrocomputer 44 counts each incoming message with a message counter 45and assigns a unique message number to that message. For example, thethird incoming message may be designated "message number 3". The messagenumber of the message presently being recorded by the ICM tape drive 16is stored in the RAM 48 for recording on the message track.

The microcomputer 44 further has a time clock 47 which is read at thestart of the incoming message. The time that the message started is thentemporarily stored in the RAM 48 while the message is being recorded.The microcomputer 44 further has a calendar 49 which is also read at thebeginning of each incoming message. Thus, the date of the message isalso temporarily stored in the RAM 48 together with the message numberand the time that the message was received. In the illustratedembodiment, the message counter, clock and calendar functions areinternally implemented by the microcomputer together with the programstored in the ROM 40. Alternatively, a dedicated clock circuit, messagecounter and date computing circuit may be utilized to implement thesefunctions.

While the incoming message is being recorded on the message track of theICM recorder 16, the microcomputer 44 continuously amd repetitivelytransmits the message identifcation information, stored in the RAM 48,in digital form to a data modulator 82 for recording on the data trackof the ICM tape 15 via the message track recording head 94. The datamodulator 82 transforms the digital message identification signals fromthe microcomputer 44 to a form suitable for recording on the data trackof the ICM tape 15.

The data modulator 82 is schematically shown in greater detail in FIG.3. The modulator 82 includes an oscillator 84 which produces acontinuous audio tone represented by the waveform 86. The digitalmessage identification signals from the microcomputer 44 are presentedto the input of a controller 88 which controls an analog switch 90. Theswitch 90 is connected to the output of the oscillator 84 and is closedby the controller 88 in response to a logical 1 from the computer.Conversely, the controller 88 opens the switch 90 in response to alogical 0, in the illustrated embodiment.

The output of the switch 90 is connected to an amplifier 92, the outputof which is connected to the ICM data record/playback head 94. Toillustrate the operation of the data modulation 82, FIG. 3 shows aportion of a digital message identification waveform 96 which has twological 1's, or pulses presented at the input of the controller 88. Thetwo digital pulses cause the analog switch 90 to close and open twicemodulating the audio tone to produce two audio modulated pulses orbursts as represented by the waveform 98 at the output of the amplifier92. The modulated digital message identification signals at the outputof the amplifier 92 are outputted to the ICM data record/playback head94 for recording on the message track of the ICM tape 15.

FIG. 4 shows an example of one format in which the digital messageidentification data may be transmitted from the microcomputer 44 andrecorded on the message track. The message data of the illustratedembodiment is shown as a series of groups of pulses separated by 50millisecond spaces. Each pulse within a group is separated by a 10millisecond space. The first message identification data is the messagenumber which has four digits. In the example of FIG. 4, there are fourgroups of pulses (representing the four digits) preceeded by a 100millisecond pulse. In the coding scheme of the illustrated embodiment,ten pulses represent a decimal 0 and the remaining decimal digits, 1-9,are represented by a corresponding number of pulses. Thus, the initialthree groups of ten pulses followed by the group of two pulses of thewaveform of FIG. 4 represent message number "0002". It is recognized ofcourse that other digital coding schemes may be used such asbinary-coded-decimal (BCD), for example.

The message number is repeated two more times and is followed by a 100millisecond space. After an initial 150 millisecond pulse, there arefour more groups of pulses (representing four decimal digits) whichindicate the date that the message was received. The first two groups ofpulses designate the month that the message was received and the lasttwo represent the day of the month. The message date data is alsorepeated two times. After an initial 300 millisecond pulse there arefour groups of pulses which indicate the time that the message wasrecorded. The time data is also repeated two times.

A flow chart representing the microcomputer program for recording theincoming messages is shown in FIG. 8. This program (or subprogram) isinitiated by the 800 hertz tone recorded at the end of the announcementon the OGA tape. The 800 hertz tone is detected by the tone decoder 78(FIG. 2) which initiates execution of the program of FIG. 8 and thus therecording of the incoming message, as indicated in block 100 of FIG. 8.Upon detection of the 800 hertz tone, the microcomputer 44 starts atimer (102) to set a maximum duration for the message to be recorded bythe caller. The user has the option of setting a five minute or 30second limit in the illustrated embodiment. Since a new message is beingrecorded, the message counter of the microcomputer 44 is incremented(104) so that the counter indicates the new message number. Next, a"CALLS" flag is set (106) and a "CALLS" LED 108 is illuminated (FIG. 1)to indicate to the user that at least one message has been received andrecorded.

The microcomputer 44 reads (110) the message counter 45 to determine themessage number of the incoming message and also reads the calendar 49and clock 47 to determine the date and time of the incoming message.This message identification information is stored in digital form in themicrocomputer RAM 48 in preparation for transmission to the ICM tapedrive 16 (FIG. 1) to be recorded on the message track. Recording of theincoming message is begun by starting (112) the ICM motor 42 andselecting the ICM record/playback message head 68. As the callerdictates and telephone answering device records his message onto themessage track of the ICM tape 15, the microcomputer 44 transmits (114)the digital signals representing the message number to the datamodulator 82 for recording on the data track of the ICM recorder 16. Themessage number is transmitted three times for error checking purposes aswill be more fully explained below. After the message number data, themessage date data (116) and the message time data (118) are eachtransmitted three times to the data track as shown in the example ofFIG. 4.

If the caller has not finished dictating the message (120) the timer isexamined (122) to determine if the alloted time for the message hasexpired. Referring to FIG. 2, the answering device 10 has a VOX detectorcircuit 124 connected to the amplifier 80. The VOX detector circuit 124monitors the incoming message and produces an output to themicrocomputer 44 when the voice signal is absent. If the voice signal isabsent for a certain minimum time (for example, three seconds) themicrocomputer 44 will assume that the caller is finished and that themessage is complete. The answering device 10 optionally also has ahang-up detector 126 which provides an output to the microcomputer 44 asto when the caller hangs up. This provides an additional indication tothe microcomputer 44 when the incoming message has been completed. Ifthe message has not been completed and the time has not expired, themicrocomputer again transmits the message identification signals (114,116, 118) to the ICM tape drive 16 for recording on the data track. Inthis manner, the message identification signals are continuouslyrecorded on the data track while the incoming message is recorded on themessage track of the ICM tape 15.

When the microcomputer 44 determines that the incoming message has beencompleted, the microcomputer 44 stops sending the message data and afive second blank is recorded (128) on the data track at the end of thedigital message identification signals. FIG. 5 is a waveformrepresentation of the modulated digital message signals for severalmessages on the data track. In the illustrated embodiment, throughouteach message there are no blanks or spaces between individual pulses orbursts on the data track, which are greater than 100 milliseconds induration. Thus, the five second blank on the data track at the end ofthe message identification data unambiguously identifies the end of anincoming message on the message track (and hence the beginning of thenext incoming message to be recorded on the message track).

As the incoming message is recorded, the ICM tape 15 is unwound from thesupply side of the cassette and is wound on the take-up side of thecassette. The supply side spindle or shaft from which the tape 15 isunwound, will rotate faster as the tape is used up. The device 10 has aspindle tachometer 129 (FIG. 2) which is coupled to the supply spindleand monitors the rotational speed of the supply spindle.

The speed of the supply spindle corresponds to the amount of ICM tapeleft on the supply spindle. A maximum spindle speed detector 131 isconnected to the output of the tachometer 129 and provides an output tothe microcomputer 44 when the speed of the supply spindle exceeds apredetermined threshold. In the illustrated embodiment, this thresholdcorresponds to an amount of tape left on the supply side spindle whichequals the maximum tape necessary to record an incoming message. Thus,when the detector 131 signals the microcomputer 44 that the amount ofICM tape 15 left is less than or equal to one message length, themicrocomputer 44 will not record any additional message after the onepresently being recorded. The device 10 has a separate "announcementonly" message recorded on the second track of the OGA tape 13 which doesnot instruct the caller to leave a message. Thus, the announcement onlymessage is played when a call is received instead of the regularannouncement, when the ICM tape 15 is almost used up.

Referring back to FIG. 8, upon completion of the recording of the fivesecond blank, the incoming message motor 64 is stopped (130) and themicrocomputer 44 returns (132) to other tasks i.e., a monitor routinewhich places the microcomputer 44 in readiness to detect the next call.The above-described process is repeated for each incoming message. Eachincoming message is recorded on the message track of the ICM tape 15,while simultaneously, the message number and date and time the messagewas received are continuously recorded on the data track of the ICM tape15. Upon completion of the message, a five second blank is recorded onthe data track to mark the end of that message and also the beginning ofthe next message, if any.

When the user desires to listen to the recorded incoming messages, hefirst checks to see if the "CALLS" LED 108 (FIG. 1) is lit. If not, thenthe user has not received any calls. If the calls LED 108 indicates thatmessages have been received, the user may depress a "PLAYBACK" switch orkey 134 on the front of the answering device 10 to replay the recordedmessages. As an additional feature of the illustrated embodiment, themicrocomputer 44, upon closure of the playback key 134, automaticallycontrols the ICM tape drive 16 to rewind the ICM tape 15 to thebeginning of the first message received. To determine the location ofthe beginning of the first message, the microcomputer 44 utilizes themessage numbers assigned to the incoming messages, as will be more fullyexplained below.

Referring now to FIG. 2, when the ICM tape 15 is positioned at thebeginning of the first message, the ICM record/playback message head 68is selected and the ICM tape drive 16 is placed into the playback mode.The incoming messages recorded on the message track are played backthrough a speaker 136 connected to the output of an amplifier 138. Theamplifier 138 is in turn connected to the output of the amplifer 72 ofthe ICM record/playback head 68. While a message is being played backthrough the speaker 136, the message identification signals recorded onthe data track of the ICM tape 15 for that particular message aresimultaneously played back through the ICM data record/playback head 94.These message identification signals are amplified and demodulated by anamplifier and tone decoder 140. The tone decoder 140 reconverts themodulated digital message identification signals represented in FIG. 5back to the unmodulated square waveform shown in FIG. 4. The demodulatedmessage identification signals from the message track are inputted bythe microcomputer 44 which sequentially displays the message number anddate and time the message was received on the display 18 while thatmessage is being played back through the speaker 136.

In addition to displaying the message number of the message beingplayed, the microcomputer 44 also compares this message number with themessage number of the last message recorded. When this last messagenumber is encountered, indicating that the last message is being playedback, the answering device 10 automatically stops playback at the end ofthe message.

As an additional advantage of the illustrated embodiment, if the user,upon completion of the normal playback, desires to listen to aparticular message again, the facility is provided for entering themessage number of the desired message into the answering device 10. Whenthe playback key is depressed, the device 10 will automatically rewindthe ICM tape to the beginning of that message and begin playback. Thisis another message selection feature in addition to the cue functionalready described. If no message number is selected prior to depressingthe playback key, the device 10 automatically rewinds to the beginningof the first message and begins playback.

To enter the number of the desired message, a mode key 150 on the frontof the answering device 10 is repeatedly depressed until the MSGNO.(message number) LED 22 is lit indicating that the device is in themessage number mode. The first digit of the message number may then beentered by depressing a switch 152 and then releasing the switch whenthe desired digit appears in the position 154 of the display 18. Thedisplay 18 automatically displays the digits 0-9 rapidly in sequenceuntil the switch 152 is released, freezing a particular digit inposition 154. The last two digits of the message number may be similarlyentered by depressing a key 160 and releasing when the desired digitsappear in the two right digit positions 156 and 158 of the display 18.With the message number of the desired message indicated in the display18, the "ENTER" key 162 may be depressed which causes the answeringdevice 10 to temporarily store the selected message number in the RAM48. When the playback key 134 is depressed, the device 10 automaticallyrewinds the ICM tape to the beginning of the message corresponding tothe entered message number to play back the selected message.

These playback features are described in greater detail in FIGS. 9A-Bwhich show a flow chart of the microcomputer operation during playback.The program is initiated when the microcomputer 44 senses that theplayback key 134 has been depressed (166). If no calls have beenreceived (168) by the answering device 10, the microcomputer 44 returns(170) to other tasks. If calls have been received, then the "present"message number is compared (172) with the message number shown in thedisplay 18. The "present" message number is the message number of thelast message replayed. If the "present" message number differs from themessage number shown in the display, this indicates to the microcomputer44 that the user has entered a new message number for replay. If thepresent message number is greater than the message number shown in thedisplay, the ICM tape 15 is rewound (174). As the ICM tape is rewound,the five second blanks on the data track between messages are counted(176) until the correct number of blanks has been passed (178) to bringthe ICM tape to the beginning of the message corresponding to theentered message number. For example, if the message number of the lastmessage played, that is, the present message number, is 7 and messagenumber 5 has been entered into the display 18, then the third fivesecond blank encountered as the ICM tape is rewound will be thebeginning of message number 5. At that time, the ICM tape is stopped andthe playback of message number 5 is begun (180). The microcomputer 44monitors the 5 second blanks on the data track through the tone decoder140 of FIG. 2.

Alternatively, if the present message number is less (172) than themessage number entered in the display 18 then the incoming message tapeis fast forwarded (182) if the entered message number is less than orequal (183) to the message counter. As previously mentioned, the messagecounter indicates the message number of the last incoming messagerecorded. Thus, if the entered message number is greater than themessage counter, the user is attempting to play back a messagecorresponding to a message number not yet recorded. In which case, themicrocomputer 44 returns (184) to other tasks.

If the user has not selected a particular message number for replay(i.e., normal replay) and the user has not previously rewound or fastforwarded the ICM tape (186) before pressing the playback switch 164,the present message number is compared with the "initial" message number(188). The "initial" message number is the message number of the firstmessage recorded after the "ANSWER SET" key 190 (FIG. 1) is pressed. Theanswer set key enables the answering device 10 to begin answering calls.If the present message number is greater or equal to the initial messagenumber, the ICM tape is rewound (174) to the beginning of the messagecorresponding to the initial message number (176 and 178). In thismanner, upon depressing the playback key 164 (if the user has notentered a particular message number for replay), the ICM tape isautomatically rewound to the beginning of the initial message of the setof messages recorded since the answer set key was activated.

As an example of an "initial" message, if two message are initiallyrecorded, they will be assigned message numbers 1 and 2, respectively.These messages may be played back, and after playback of message number2, the last message, the answering device will automatically stop. Theanswer set key 190 can then be depressed which enables the answeringdevice to receive more calls. The next message received will be assignedmessage number 3 and 3 is the new "initial" message number. Thus, afteradditional calls are received and recorded, upon depressing the playbackkey 134, the answering device 10 will automatically rewind to thebeginning of message number 3.

After the ICM tape 15 is rewound (or fast forwarded) to the beginning ofthe desired message, playback is begun (180). As the message on themessage track is replayed through the speaker 136 (FIG. 2), themicrocomputer 44 reads the message number, date and time data (192) fromthe ICM tape data track. As previously noted, the message number data isrecorded three times in a row. The three message numbers are compared(194) and if two or more agree then the consensus message number isstored (196) in RAM 48 as the "present" message number. In addition, themessage number is displayed by the display 18 for three seconds (198)with the MSG. No. LED 22 (FIG. 1) also illuminated to indicate that thenumber in the display 18 is the message number of the message beingplayed. In a similar manner, the three message dates are compared (200)and if two or more agree, the date is displayed (202) in the display 18.In addition, the date LED 26 is lit indicating that the number shown inthe display 18 is the date that the message being played was received.The message time data is treated in a similar manner (204 and 206).

If the message number of the message presently being played is thenumber of the last message recorded (208) as indicated by the messagecounter of the microcomputer 44, then the ICM tape 15 has reached thelast message recorded. Otherwise the microcomputer continues to read themessage data (192) and display it. At the end of the last message (210)the ICM motor 64 is stopped (212) and the microcomputer 44 returns(214).

In addition to the user entering the message number of a particularmessage for replay, the telephone answering device 10 of the presentinvention has a cue memory by which the user may select particularmessages for later replay. As previously mentioned, as each message isbeing replayed, the message number for that particular message isdisplayed by the display 18. If the cue key 28 (FIG. 1) is depressedduring the replay of a message, the message number is stored in a cuememory which is a portion of the RAM 48 (FIG. 2). As other messages areplayed back, the user may select additional messages for replay bydepressing the cue key 28 while the selected message is being playedback.

After the user has completed playing back all the messages, the user canreplay the last message cued by again depressing the cue key 28. Theanswering device 10 will automatically rewind the ICM tape 15 to thebeginning of the last message cued and replay that message. The ICM tapedrive 16 will then automatically stop at the end of the message. If theuser again depresses the cue key 28, the next to last cued message willthen be replayed. In the illustrated embodiment, up to three suchmessages may be cued and later replayed. The cue memory feature isdescribed in greater detail in the microcomputer program flowchart ofFIG. 10.

When the microcomputer 44 senses that the cue key 28 has been depressed(230), the microcomputer 44 determines whether the ICM tape drive 16 isstopped or is playing back messages (232). If the ICM tape drive 16 isstopped or is playing back messages (232). If the ICM tape drive 16 isin the proceaying back a message, then the user has depressed the cuekey 28 to select that message for later playback In which case, themicrocomputer 44 determines if the cue memory of the RAM 48 is full(234). In the illustrated embodiment the cue memory can hold up to threemessage numbers. If the cue memory is full, the microcomputer 44 ignores(236) the cue key 28 while the ICM tape drive 16 is in playback. If thecue memory is not full, the microcomputer 44 stores (238) the messagenumber of the message being played into the cue memory of the RAM 48.

If the ICM tape drive 16 is stopped (232) when the cue key 28 isdepressed, the microcomputer 44 determines if any message numbers havebeen stored (240) in the cue memory. In the illustrated embodiment, thelast message number stored in the cue memory is the first message whichis replayed. The microcomputer 44 compares (242) the last message numberstored in the cue memory with the present message number (which is themessage number of the last message played). ln other words, themicrocomputer 44 compares the message number of the message to bereplayed with the present location of the ICM tape 15 of the ICM tapedrive 16. If the cued message is located preceding the present locationof the ICM tape, the ICM tape is rewound (244) and the blanks on thedata track marking the end or beginning of each message on the messagetrack are counted (246) until the beginning of the cued message islocated (248). For example, if the cued message has message number 27,and the message number of the last message replayed is message number31, then after five blanks are counted, the playback head 68 of the ICMtape drive 16 will be positioned at the beginning of the cued message(number 27). When the fifth blank is encountered, playback is initated(250) and the last message number in the cue memory (27 in this example)is cleared (252).

The playback of the cued message is complete when a blank is encounteredon the data track (254) marking the end of the message on the messagetrack and the ICM tape is stopped (256). The cue memory program ends(258) and the microcomputer 44 halts or returns to other tasks. If thecue key 28 is again depressed (230) the next message number stored inthe cue memory is examined (242) and the ICM tape 15 is rewound (244) tothe beginning of the cued message. If the message number of thepreceeding cued message exceeds the present message number (242), theICM tape is fast forwarded (260) to the beginning of the cued message.

Another feature of the illustrated answering device 10 allows the userto skip over unwanted portions of messages during playback of themessages. The answering device 10 has a "NEXT MESSAGE" key 270 (FIG. 1),which causes the ICM tape drive 16 to switch from playback mode to fastforward and fast forward the ICM tape to the beginning of the nextmessage. FIG. 11 illustrates the manner in which the microcomputer 44implements this function. When the microcomputer senses that the nextmessage key 270 has been depressed (272), the microcomputer 44determines whether the ICM tape drive 16 is in the playback or stopmode. If the ICM tape drive 16 is stopped, the microcomputer 44 ignores(276) the next message key 270. If the ICM tape drive 16 is in playbackmode, the ICM forward-rewind drive transfer mechanism is actuated (278)and the ICM tape drive 16 is switched from playback to fast forwardmode. (The transfer mechanism or plunger is actuated by a solenoid whichis energized by a driver 280 (FIG. 2) controlled by the microcomputer 44through the output interface 58.) At this time, a "PLAYBACK" LED 282(FIG. 1) is extinguished, indicating that the answering device 10 is nolonger in playback mode.

The microcomputer 44 then monitors the data track on the ICM tape 15through the tone decoder 140 (FIG. 2) while the tape is fast forwarded.If a blank is immediately encountered (283) which is greater than onesecond in duration (284), then all the messages have probably beenalready played and the remaining ICM tape is blank. In which case, theICM tape drive 16 step, (286). If no initial blank is found (283), themicrocomputer 44 continues to monitor the data track of the ICM tape 15until a blank is encountered (288).

As previously mentioned, the message identification information signalsare recorded on the data track with a 10 millisecond blank or spacebetween individual pulses and a 50 millisecond blank between numbers (orgroups of pulses). In addition, a 100 millisecond blank is placedbetween the message number data, the message date data, and the messagetime data. Between messages however, a 5 second blank is recorded whichmarks the beginning and end of each message. Thus, until a blank spacewhich is greater than 100 milliseconds is encountered, the ICM recorder16 is still in the middle of a message. Accordingly, when a blank inexcess of 100 milliseconds is encountered, the transfer mechanism isdeactuated (290), returning the ICM tape drive 16 to playback mode andthe playback LED 282 is lit. Since the maximum duration of a blank onthe data track within a message is 100 milliseconds (see FIG. 4), thenany blank in excess of 100 milliseconds on the data track unambiguouslyindicates the end (or beginning) of a message (see FIG. 5).

On the message track, however, relatively long blanks are often recordedwithin a message as the caller pauses between words while dictating.Thus, previous devices which monitor the message track for the end ofthe message can be confused by these pauses. The blank duration of 100milliseconds between message data types and the blank duration of 5seconds between entire messages on the data track are provided forpurposes of illustration only. Of course, other durations may besubstituted for those described for the illustrated embodiment. Inaddition, if the message data is not desired, a single continuous audiotone may be recorded on the data track while a message is recorded onthe message track, with a blank placed in the data track to mark the endof the message.

As previously mentioned, the incoming message tapes are frequently usedover and over such that new messages are recorded over old messages.Furthermore, the user, after playing back messages, may set theanswering device in the answer mode before the ICM tape drive 16 hasreached the end of a particular message. It is undesirable to start therecording of a new message in the middle of an old prerecorded messagesince the data tracks for the two messages would run together. In orderto prevent this, the microcomputer 44 sets a "midway position" flagwhenever the ICM tape drive 16 is stopped at any location other than theend of the message. In the illustrated embodiment, the end is marked bya a 5 second blank on the data track. This flag is also set whenever atape is initially loaded.

Referring now to FIG. 12, a flow chart describing the initial operationof the microcomputer 44 when a call is received by the answering device10 is shown. When the microcomputer 44 detects an incoming call (292)from the ring detector 54 (FIG. 2), the microcomputer 44 starts the OGAmotor of the OGA tape drive 14 to begin playing the announcement (294).If the midway position flag is set (296) (indicating that the ICM tape15 of the ICM tape drive 16 is stopped at a position other than at theend of a message), the ICM tape 15 is fast forwarded (298) until theblank (in excess of 100 milliseconds) on the data track at the end ofthe message is encountered (300). The ICM tape drive 16 is then stopped(302). The ICM tape 15 of the ICM recorder 16 is now in position torecord the new incoming message. In addition, there is a blank in excessof 100 milliseconds on the data track separating the messageidentification information of the old message from the messageidentification information of the new message.

With the ICM tape 15 positioned at the end of the old message, themicrocomputer 44 waits for the end of the announcement (304) recorded onthe OGA tape 13. As previously mentioned, an 800 hertz tone reorded onthe OGA tape marks the end of the announcement. When the 800 hertz toneis detected by the tone decoder 78 (FIG. 2) the recording of theincoming message is started as described in FIG. 8.

The above described feature is also applicable to other "end of message"descrimination systems. For example, other answering devices may monitorthe message track for pauses of a predetermined length to locate the endof the message.

Referring now to FIG. 1, most of the answering device 10 functions suchas stop, rewind, fast forward, cue, next message, etc., can becontrolled from the remote control unit 30. As will be more fullyexplained below, as each function key of the key pad 32 of the remotecontrol unit 30 is depressed, a digital function code is transmittedfrom the speaker 36 (FIG. 2), over the telephone line 12 and into theanswering device 10 where it is decoded and implemented. However, beforethe answering device 10 will accept and implement function codes from aremote control unit, the correct digital security code must betransmitted by the control unit to the answering device 10. In theillustrated embodiment, the remote control unit 30 automaticallytransmits the security code when an "ON/OFF" key 310 is moved to the"on" position.

When the answering device 10 receives a security code from a remotecontrol unit, the microcomputer 44 compares the transmitted securitycode with an expected security code which is stored in the RAM 48.Accordingly, when the remote control unit 30 is set or programmed for aparticular security code, it is very important that the security code beaccurately set so that the answering device 10 will recognize the user'sremote control unit. Thus, if the user decides to change the securitycode, then it is quite important that the security codes stored by theanswering device 10 and the remote control unit 30 are changed to thesame code. In order to insure this, a cable 42 is provided to connectthe remote control unit 30 to the answering device 10 when the userenters a new security code. As will become more clear in the followingdescription, when the user changes the expected security code of theanswering device 10, the same security code which the remote controlunit 30 will transmit is automatically changed to the new expectedsecurity code of the device 10.

To enter a new security code, the user presses a "CODE" key 312 on thefront of the answering device 10. The new security code is then enteredinto the display 18 by pressing and releasing the switches 152 and 160in the same manner as the entry of a message number for playback asearlier described. When the desired new security code appears in thedisplay 18, the enter key 162 is depressed causing the microcomputer 44to input the new security code and store it in the RAM 48 (FIG. 2). Theanswering device 10 will now respond only to remote control units whichfirst transmit the new security code.

The answering device 10 has an input line 314 (FIG. 2) connected to asecurity code output line 316. Through the input line 314, themicrocomputer 44 is able to detect when the cable 42 is connectedbetween the answering device 10 and the remote control unit 30. In theillustrated embodiment, the remote control unit 30 also has amicrocomputer 318 which in turn has a program read only memory (or ROM)320 and a random access memory (RAM) 322. The cable connector 42 isconnected to a driver 324 which is connected to an input of themicrocomputer 318.

Referring now to FIG. 13, a flow chart is shown which describes themanner in which the microcomputer 44 automatically transmits the newsecurity code to the microcomputer 318 of the remote control unit 30.When the microcomputer 44 senses that the enter key 162 has beendepressed (320), the microcomputer 44 inputs the new security code (332)indicated in the display 18. (The microcomputer 44 detects the earlierclosing of the code key 312 in order to distinguish the entering of anew security code from the entering of a message number, date set ortime set with the mode key 150.) If the microcomputer 44 senses throughthe input line 314 that the connector cable 42 has been connected (334)between the answering device 10 and the remote control unit 30, themicrocomputer 44 stores the new security code in the RAM 48 andtransmits the new security code (336) three times over the connectorcable 42 to the microcomputer 318 via the driver 324.

FIG. 7A illustrates a waveform representing the format in which adigital security code may be sent to the remote control unit 30. Thewaveform has four groups of pulses, each of which represents a digit. Inthe coding scheme of the illustrated embodiment, a digit is representedby a corresponding number of digital pulses. Thus, the example shown inFIG. 7A represents the security code "1234". This is repeated threetimes.

The flow chart shown in FIG. 14 describes the manner in which themicrocomputer 318 of the remote control unit 30 inputs the new securitycode transmitted by the microcomputer 44 of the answering device 10. Ifa key of the key pad 32 is depressed or the on/off switch 310 is movedto the "on" position, the microcomputer 318 is activated (338) (i.e.removed from the "halt" status). If the output from the driver 324indicates that the connector cable 42 is connected to the remote controlunit 30 (340), the microcomputer 318 reads the digital security code(342) transmitted three times from the microcomputer 44 in the answeringdevice 10. Since the security code is transmitted three times, themicrocomputer 318 can compare the three examples of the security code tosee if the three examples agree (344). If the three codes do not agree,that is, are not identical, then the new security code entered isignored (346). However, if the three security codes do agree, then theyare further examined (348) to insure that each has four digits. If thecodes pass this error check, the microcomputer 318 stores the newsecurity code (350) into the RAM 322 of the microcomputer 318. Inaddition, a tone from the speaker 36 (FIG. 2) is outputted (352) toindicate to the user that the security code has been accepted.

In this manner, a new security code entered into the answering device 10is automatically entered into the remote control unit 30. In addition,an error check is performed to insure that no error has occurred in thetransmission of the security code. Thus, it is seen that a new securitycode may be reliably entered into both the answering device 10 and theremote control unit 30 to insure that the answering device 10 willrespond to the remote control unit 30.

In order to use the remote control unit 30, the user first dials thetelephone number of the answering device 10. When the device 10 respondsby playing the announcement from the OGA tape drive 14, the user placesthe speaker 36 of the remote control unit 30 against the mouth piece ofthe hand set of the telephone. The remote control unit 30 is then turnedon by placing the on/off switch 310 (FIG. 2) to the "on" position. Thiscauses the microcomputer 318 to transmit the security code stored in theRAM 322 to the answering device 10.

After the security code is transmitted, if any function key of the keypad 32 is depressed, the remote control unit 30 will transmit thefunction code for that function key to the answering device 10 to becarried out. For example, if the playback key 134a is depressed, theremote control unit 30 will transmit the function code for playback tothe answering device 10. If the correct security code has beentransmitted by the remote control unit 30, the answering device 10 willautomatically rewind the ICM tape and begin playing back the recordedmessages.

The remote control unit 30 has an oscillator 360 connected to an outputof the microcomputer 318. The output of the oscillator 36 is modulatedby the security code and function codes outputted by the microcomputer318 for transmission over the telephone line 12. The output of theoscillator 360 is connected to the speaker 36 which is placed againstthe mouthpiece of the telephone.

In the illustrated embodiment, the digital security code and functioncodes of the remote control unit 30 are transmitted over the telephoneline using the frequency shift key technique. This technique isillustrated in FIG. 6A. To transmit a logical one, the oscillator 360produces an audio tone at a frequency f₁ and produces a second audiotone at a second frequency f₂ to transmit a logical zero.

Referring back to FIG. 2, the modulated code signals from the remotecontrol unit 30 are received over the telephone line 12 and amplifiedand filtered by the filter 38 which attenuates or substantially removesthe second audio tone (at the frequency f₂) from the transmittedmodulated code signals as shown in FIG. 6B. The tone decoder 40 respondsto the first audio tone (at frequency f₁) to output a logical one andotherwise outputs a logical zero, to produce two pulses as shown in theexample of FIG. 6C.

In the illustrated embodiment, the security codes are transmitted overthe telephone line 12 in the same format as when transmitted over thecable 42. Thus, except for the modulation of the pulses for transmissionover the telephone lines, FIG. 7A is a representative example of theformat and digital coding scheme for both. Other formats and codingschemes such as BCD are, of course, possible.

The functions are digitally coded and modulated for transmission in asimilar manner. However, the function codes have a single number in theillustrated embodiment. An example of a possible assignment scheme for10 answering device functions is detailed in the following table:

                  TABLE                                                           ______________________________________                                        Number               Number of                                                of Pulses                                                                            Function      Pulses    Function                                       ______________________________________                                        1      PLAYBACK      6         FAST FORWARD                                   2      STOP          7         CUE                                            3      BACK SPACE    8         ANSWER SET                                     4      NEXT MESSAGE  9         ANNOUNCE                                                                      CHANGE                                         5      REWIND        10        ANNOUNCE                                                                      RECORD                                         ______________________________________                                    

Thus, for example, when the "stop" function key 361 is depressed on theremote control unit 30, two pulses are outputted by the microcomputer318 as shown in FIG. 7B. Each function code is preceeded and followed bya 150 millisecond pulse as shown in FIG. 7B.

The pulses from the microcomputer 318 are modulated by the oscillator360 and transmitted to the telephone line 12 by the speaker 36 Themodulated function code is filtered by the filter 38 and demodulated bythe tone decoder 40 back to the unmodulated form shown in FIG. 7B. Thetwo pulses are inputted by the microcomputer 44 which decodes orrecognizes the two pulses to represent the "stop" function Themicrocomputer 318 accordingly stops the ICM tape drive 16. It is clearfrom the foregoing that additional functions may be easily controlled bymerely adding additional function code numbers without having to addadditional tone decoders such as the tone decoder 40.

The remote control of the functions is described in greater detail inthe flow chart of FIG. 14. As previously mentioned, the microcomputer318 of the remote control unit is activated by depressing a key orturning on the remote control unit 30 (338). If the security codeconnector cable 42 is not connected to the remote control unit 30 (340)the microcomputer 318 scans the key pad 32 (362). If no function key hasbeen depressed (364) (indicating that instead the on/off switch wasswitched to the "on" position), the microcomputer 318 transmits thesecurity code stored in RAM 322 (366) to the answering device 10.However, if a function key has activated the microcomputer 318 (364) themicrocomputer 318 determines which function key was depressed (368) andoutputs the corresponding function code (370) to the answering device10.

In the illustrated embodiment, the frequency of the logical one audiotone, f₁, is 3 kilohertz. Accordingly, the tone decoder 40 outputs alogical one (or pulse) when a 3 kilohertz tone is inputted into the tonedecoder 40. Referring now to FIG. 15, when the 3 kilohertz tone isinitially detected (372), the microcomputer 44 of the answering device10 inputs the digital security code (374) transmitted from the remotecontrol unit 30 and demodulated by the filter 38 and tone decoder 40(FIG. 2). (In order to prevent the inadvertent activation of the tonedecoder 40, the filter 70 filters out any 3 kilohertz tones from theoutgoing announcement). The microcomputer 44 compares (376) the inputteddigital security code from the remote control unit 30 with the expectedsecurity code which is stored in the RAM 48. If the incorrect securitycode has been transmitted, the microcomputer 44 ignores (378) anyfunction codes transmitted from that control unit (378). However, if thecorrect security code has been transmitted (376), the microcomputer 44stops (380) the outgoing announcement tape drive 16 which stops the playof the announcement. The microcomputer 44 then starts a 30 second timer(382). If the remote control unit 30 transmits a function code (384)within the 30 second limit, the function code is decoded (386) andimplemented. The microcomputer 44 then waits for another 30 seconds foranother digital function code to be transmitted. If no function code isreceived within the 30 second time limit (388), the microcomputer 44stops (390).

It will, of course, be understood that modifications of the presentinvention, and its various aspects will be apparent to those skilled inthe art, some being apparent only after study and others being merelymatters of routine electronic design. Other embodiments are alsopossible, with their specific designs dependant upon the particularapplication. For example, many of the above described features areequally applicable to dictation equipment. In addition, the controlelements are implemented with a programmed microcomputer in theillustrated embodiment. Dedicated logic can, of course, be substitutedfor these functions. As such, the scope of the invention should not belimited by the particular embodiment herein described, but should bedefined only by the appended claims and equivalents thereof.

We claim:
 1. A telephone answering device for receiving incomingmessages, comprising:message counter means for assigning a uniquemessage number to an incoming message and providing digital signalsrepresentative of the message number; processor means; recorder meanshaving a recording medium which includes first and second tracks andmeans controlled by the processor means and responsive to the digitalsignals provided by the message counter means for recording signalsrepresenting an incoming message on the first track and the digitalsignals on the second track; playback means controlled by the processormeans, for playing back incoming messages recorded on the first trackand for simultaneously reading back the digital signals recorded on thesecond track and transmitting the digital signal to the processor meanswhile the message recorded on the first track is being played back; auser manipulable input for designating a selected message number; meansresponsive to said selected message number, for controlling the playbackmeans to automatically locate on the recording medium the beginning ofthe selected message recorded on the first track which corresponds tothe selected message number; and means for replaying the messagecorresponding to the selected message number.
 2. The device of claim 1further comprising a user manipulable input for providing a playbacksignal, the processor means further having a memory for storing themessage number of the first message recorded, and the processor meanshaving means responsive to the playback signal, for controlling theplayback means to automatically locate the beginning of the firstmessage recorded and for replaying the first message.
 3. The device ofclaim 2 wherein the processor means further comprises means for storingthe message number of the last recorded message, and the processorplayback control means is responsive to the last message number to stopthe playback after the message corresponding to the last message numberhas been replayed.
 4. The device of claim 1 further comprising a usermanipulated input means for providing a cue signal, the recorder meansbeing responsive to the cue signal for replaying a selected message, anda processor cue memory means for storing the message number of a messagebeing played back in response to a cue signal.
 5. The device of claim 4wherein the processor means further comprises means for controlling theplayback means to automatically locate on the recording medium inresponse to a cue signal the beginning of the cued message correspondingto the message number stored in the cue memory and to play back the cuedmessage.
 6. In an telephone answering device in which a sequentialnumber identifying each message is recorded on an incoming message tapealong with the incoming message, an apparatus for selectively playingback a selected one or more of the messages, comprising:message numberstorage means for storing selected message numbers; first playback meansfor audibly playing back recorded messages; switch means, operative by auser during message playback, for enabling the storage in the storagemeans of the number of the message currently being played back when theuser actuates the switch means; and second playback means operative whenan initial message playout is completed, for selectively playing back asecond time, only those messages having numbers corresponding to thosestored.
 7. A telephone answering device comprising:message counter meansfor assigning a unique message number to an incoming telephone messageand for providing digital signals representative of the assigned messagenumber; recorder means having a magnetic tape which has a message trackand a data track, for recording incoming messages on the message trackand for recording the message number digital signals on the data track;playback means for playing back the messages and message number digitalsignals; a cue input for user cue input signals for the user to select amessage being played back for later replay; processor means responsiveto the counter means, for transferring the digital signals representingthe message number assigned to a particular incoming message to therecorder means to be recorded on the data track as that particularmessage is being recorded on the message track, said processor meansfurther having a cue memory and means responsive to a cue input signal,for storing the message number of the message being played back by theplayback means into the memory and means for controlling the playbackmeans to play back the messages selected by the user.
 8. The device ofclaim 7 wherein the message numbers are assigned sequentially to themessages as the messages are recorded, the processor means furthercomprising comparison means for comparing the message number of thecurrent message played with the message number stored in the cue memoryand control means responsive to the comparison means for controlling theplayback means to move the tape back if the message number of thecurrent message played is greater than the message number stored in thecue memory and to move the tape foward if the message number of thecurrent message played is less than the message number stored in the cuememory, wherein the tape is moved to the beginning of the messagecorresponding to the message number stored.
 9. The device of claim 8wherein the digital signals are recorded substantially continuously onthe data track as the message is being recorded on the message track,said processor means further having means for providing no modulationsignal to the recording means at the end of a message for apredetermined period of time forming a blank on the data track at theend of each message recorded on the message track to mark the end of onemessage and the beginning of the subsequent message, said comparisonmeans further having means for computing the difference between themessage number of the current message played and the cued message numberstored in the cue memory to determine the number of messages between thecurrent message played and the message corresponding to the messagenumber stored in the cue memory and the processor control means havingmeans responsive to the playback means for counting the number of blankson the data track as the tape is moved to locate the beginning of themessage corresponding to the message number stored in the cue memory.10. The device of claim 7 wherein the processor means has a secondmemory for storing the message number of the last message recorded onthe message track and control means responsive to the playback means forcomparing the message number of the message being played back with themessage number stored in the second memory and for stopping the playbackmeans after completion of playback of the message having the messagenumber stored in the second memory.
 11. In a telephone answering devicein which message numbers are assigned sequentially and recorded on anincoming message tape as incoming messages are recorded on the incomingmessage tape, the improvement comprising:means for storing the messagenumber of the first message to be recorded after the telephone answeringdevice is enabled to receive and record incoming messages; playbackswitch means for the user to initiate playback of the recorded messages;and means responsive to the playback switch means, (1) for determiningthe difference between the last message number recorded before playbackis initiated and the first message number stored, (2) for rewinding thetape, (3) for counting the messages as the tape is rewound, and (4) forstarting playback at the beginning of the first message.
 12. A telephoneanswering device comprising:message counter means for assigning a uniquemessage number to an incoming telephone message and for providingdigital signals representative of each message number; recorder meanshaving a magnetic tape which has a message track and a data track, forrecording incoming messages on the message track and for recording themessage number digital signals on the data track; processor means,responsive to the counter means, for transferring the digital signalsrepresenting the message number assigned to a particular incomingmessage to the recorder means to be recorded on the data track as thatparticular message is being recorded on the message track; playbackmeans for playing back the messages and message number digital signals;and a message number input for a user to input a message number of amessage for playback; said processor means further having a memory andmeans responsive to the message number input for storing the selectedmessage number into the memory and control means responsive to themessage number stored in the memory for controlling the playback meansto move the tape to the beginning of the message corresponding to themessage number stored in memory for replay.
 13. A telephone answeringdevice comprising:message counter means for assigning a unique messagenumber to a incoming telephone message and for providing digital signalsrepresentative of each message number; recorder means having a magnetictape which has a message track and a data track, for recording incomingmessages on the message track and for recording the message numberdigital signals on the data track; processor means, responsive to thecounter means, for transferring the digital signals representing themessage number assigned to a particular incoming message substantiallycontinuously to the recorder means to be recorded on the data track asthat particular message is being recorded on the message track and forproviding no signal to the recorder means for a predetermined periodupon completion of the message so that a blank is recorded on the datatrack to indicate the end of the message recorded on the message track;playback means for playing back the messages on the message track andthe signals on the data track; and detector means responsive to theplayback means for detecting the end of message blank on the data track.14. The device of claim 13 wherein the processor means further has amemory and means for storing the message number of the first messagerecorded and the message number of the last message recorded in thememory, said device further having a user input to provide a user inputsignal to initiate playback of the recorded messages, said processorfurther having means for comparing the message numbers of the first andlast recorded messages to determine the number of messages between thelast message and the first message, and means responsive to thecomparison means, the detector means and the playback signal forcontrolling the playback means to move the tape back the number ofmessages determined by the comparison means to return the tape to thebeginning of the first recorded message to begin playback.
 15. Thedevice of claim 13 further comprising a user input for the user toprovide a next message input signal to skip the playback of a message,said processor having control means responsive to the next message inputsignal and the detector means, for controlling the playback means tofast forward move the tape in response to a next message user inputsignal until the detector means detects the end of the message so thatthe playback means can then play back the next message thereby skippingover the present message being played when the next message signal wasinputted.
 16. In a telephone answering device in which incoming messagesare recorded on a first track of a tape and message identificationsignals are recorded on a second track of the tape with blanks on thesecond track separating message identification signals for differentmessages such that the blanks mark the end and beginning of adjacentmessages, the improvement comprising:first means for determining whetherthe tape has been stopped in the middle of a pre-recorded message; andsecond means, responsive to the first means, for advancing the tape tothe end of a message when it is determined that the tape had beenstopped in the middle of a message before the recording a new message isinitated wherein the initiation of recording of a new message in themiddle of an old message is prevented.
 17. The device of claim 16wherein the first means includes:detector means for detecting the blanksmarking the end and beginning of adjacent messages, while the tape ismoving; flag means for indicating, when set, that the tape is stopped inthe middle of a message; and processor means, responsive to the detectormeans, for setting the flag when the tape is stopped while a blank isnot being detected.